Fix build-test-publish workflow

As part of 8d0cc5e to remove old
code, a line too much was pruned. This workflow still requires manifest
generation for system tests.

The job to build the operator image was not alerting on failure, and
this failure went unnoticed.

Author: Zerpet

.github/workflows/build-test-publish.yml

@@ -138,6 +138,7 @@ jobs:
         kustomize edit set image \
         rabbitmqoperator/messaging-topology-operator-dev=rabbitmqoperator/messaging-topology-operator:"${RELEASE_VERSION}"
         popd
+        make generate-manifests
 
     - name: Upload operator manifests
       uses: actions/upload-artifact@v4
@@ -147,6 +148,14 @@ jobs:
         retention-days: 2
         if-no-files-found: error
 
+    - name: Notify Google Chat
+      if: failure()
+      uses: SimonScholz/google-chat-action@main
+      with:
+        webhookUrl: '${{ secrets.GOOGLE_CHAT_WEBHOOK_URL }}'
+        jobStatus: ${{ job.status }}
+        title: Messaging Topology Operator - Build Operator
+
   system_tests:
     name: Local system tests (stable k8s)
     runs-on: ubuntu-latest